Hydrolytic stability and protective properties of polyurethane oligomers based on polyester/ether/polyols

The present study deals with effect of the type and chemical character of incorporated polyester/polyether blocks on the hydrolytic stability of crosslinked polyurethane oligomers. Diffusion parameters of the investigated polyurethane oligomers, giving information concerning chemical changes taking place in neutral, basic and acidic aqueous environments, have also been determined.     

The functional role of the motor area of the cortex in the formation of riddance reactions in dogs

A model of instrumental conditioning similar to the classical model (Pavlovian) is proposed. Flexion of the ipsilateral forelimb was elicited while EDS was applied to the hind limb by stimulation of the motor area of the cortex (M1); both stimuli ceased during the raising of the forelimb. Uniform combinations of this kind led to the development of forepaw flexion reactions in response to the EDS of the hind paw. Prolongation of EDS by 3 sec following cortical stimulation led to rapid extinction of the developed reactions. Thus, the possibility of the effective instrumentalization of movements induced by stimulation of the M1 is proven. This argues that the forming "instrumental" connection (drive-motor structures) is addressed directly to the M1.     

Adsorption of methylene blue from aqueous solutions by synthetic montmorillonites of different compositions

The sorption capacity of synthetic montmorillonites of the composition Na_2x (Al_2(1–x),Mg_2x )Si₄O₁₀(OH)₂ · nH₂O (where 0 < x < 1) in relation to the methylene blue dye has been investigated. The obtained results from the data for natural samples of montmorillonite (K10) and activated carbon have been compared. The effect of the montmorillonite composition and the medium acidity on the degree of dye adsorption has been studied. The chemical composition of montmorillonite, which is optimal for solving tasks in the field of ecology and medicine, has been determined. The character of the interaction of montmorillonites with the adsorbed substance from the point of view of the physical-chemical sorption models has also been studied.     

Comparative Effects of Deferiprone and Salinomycin on Lead-Induced Disturbance in the Homeostasis of Intrarenal Essential Elements in Mice

Lead (Pb) exposure induces severe nephrotoxic effects in humans and animals. Herein, we compare the effects of two chelating agents, salinomycin and deferiprone, on Pb-induced renal alterations in mice and in the homeostasis of essential elements. Adult male mice (Institute of Cancer Research (ICR)) were randomized into four groups: control (Ctrl)—untreated mice administered distilled water for 28 days; Pb-exposed group (Pb)—mice administered orally an average daily dose of 80 mg/kg body weight (BW) lead (II) nitrate (Pb(NO₃)₂) during the first two weeks of the experimental protocol followed by the administration of distilled water for another two weeks; salinomycin-treated (Pb + Sal) group—Pb-exposed mice, administered an average daily dose of 16 mg/kg BW salinomycin for two weeks; deferiprone-treated (Pb + Def) group—Pb-exposed mice, administered an average daily dose of 20 mg/kg BW deferiprone for 14 days. The exposure of mice to Pb induced significant accumulation of the toxic metal in the kidneys and elicited inflammation with leukocyte infiltrations near the glomerulus. Biochemical analysis of the sera revealed that Pb significantly altered the renal function markers. Pb-induced renal toxicity was accompanied by a significant decrease in the endogenous renal concentrations of phosphorous (P), calcium (Ca), copper (Cu) and selenium (Se). In contrast to deferiprone, salinomycin significantly improved renal morphology in Pb-treated mice and decreased the Pb content by 13.62% compared to the Pb-exposed group. There was also a mild decrease in the renal endogenous concentration of magnesium (Mg) and elevation of the renal concentration of iron (Fe) in the salinomycin-treated group compared to controls. Overall, the results demonstrated that salinomycin is a more effective chelating agent for the treatment of Pb-induced alterations in renal morphology compared to deferiprone.     

Chemical composition and distribution of the components of valley peat from Amur oblast

The chemical composition of sedge peat from the Egor’evskoe deposit as lowland peat from Amur oblast was characterized. The elemental composition of organic matter and mineral macro- and microcomponents was studied, and the distribution of bitumens, their fractions, and humic acids in the depth of occurrence was revealed. It was found that peat genesis processes occur over the entire vertical profile, and the most converted organic matter is formed at a depth of to 90 cm. The individual composition of alkane fractions consists of C₁₃–C₃₆ normal structure homologues with a carbon preference index somewhat higher than unity; the presence of pristane, phytane, and farnezane was detected. In the fractions of fatty acids, predominantly even compounds from C₁₀ to C₃₀ were identified with special distribution features at the separate stages of peat formation. The analysis of the individual composition of n-alkanes and fatty acids made it possible to supplement botanical characteristics with information on the contribution of macrophytes, algal material, and microorganisms to the formation of the organic matter of peat.     

Structural studies of a ferromagnetic GaMnSb layer

The crystalline structure and composition of a GaMnSb film is studied. The film is produced on a GaAs (100) substrate by deposition from laser plasma in a hydrogen flux at a temperature of 400°C. The formation of GaMn inclusions in the GaSb:Mn matrix is detected. The stoichiometry ratio of the inclusions corresponds to that of the Ga_162.5Mn_101.5 compound.     

Control of Low-Field Hysteresis Loop Shift of Spin Valves

Spin valves that comprise synthetic antiferromagnet as a component of pinned layer and an exchange-coupled ferromagnet/Ru/ferromagnet structure in the free layer have been prepared by magnetron sputtering. Microobjects have been formed from spin valves by optical and electron-beam lithography. It has been shown that the shift of the low-field magnetoresistance hysteresis loop decreases as the thicknes of the Ru spacer in the free layer of spin valve increases. The almost hysteresis-free odd-field dependences of the magnetoresistance were obtained for micron-sized samples; in this case, the sensitivity is 0.2%/Oe.     

Interaction of the surface of ribbons of amorphous soft-magnetic iron-based alloys with water and their magnetic properties

The effect of interaction of the surface of ribbons of amorphous soft-magnetic alloys with water on the magnetization distribution and magnetic properties has been investigated on the example of ribbons of amorphous rapidly quenched alloys Fe₈₁B₁₃Si₄C₂ and Fe₇₇Ni₁Si₉B₁₃. It has been shown by these investigations that the interaction of the surface of ribbons of amorphous silicon-containing soft-magnetic iron-based alloys with water leads to a reduction in the maximum magnetic permeability. The decrease in μ_max is caused by a magnetization redistribution in the plane of the ribbon, namely, by an increase in the volume of domains with an in-plane magnetization oriented transversely to its axis. This is connected with the formation in this direction, due to a locally directed ordering, of an enhanced concentration of atoms incorporated into the ribbon surface and inducing a pseudo-uniaxial tension that favors a reorientation of the magnetization. The degree of changes in the magnetic properties depends on the temperature of water.